It isnt D because, the passages arent focused on how they are connected. It focuses on the information provided, and the facts. It mostly is about the history. If it was connected it would have information from the other paragraphs like lets say, the paragraph, "Keeping Track of the Years" Would have a lot more information from the passage, "The Beginnings of Agriculture". But it adds on more information and facts like it in chronological order.
Then to answer your questions about facts. They include some facts then the rest is just history based. Like they are telling the story of the agricultural revolution and they add in facts like the time and numbers. So it adds some facts but its mostly history. Although history is facts. But when they mean "some facts interwoven" they mean the geography, time, and other factors.